The present invention relates to an improved screw head nail. More particularly, it relates to a screw head nail having a cylindrical bore which is designed to receive a cylindrical machine screw and which is provided with a uniquely configured nail head to prevent obstruction of the cylindrical bore upon hammering of the nail into a workpiece.
Screw head nails have been used for many years for a variety of purposes. For example, in U.S. Pat. No. 309,817, an ornamental screw head is disclosed which includes a headless nail which, after the nail is hammered into a workpiece, is covered by an ornamental screw head having a threaded tapered shaft which is received within the tapered threaded bore of the nail (a somewhat similar fastening device for screws is disclosed in U.S. Pat. No. 722,046).
In addition, screws are known (see U.S. Pat. No. 824,983), the screw head of which have a central cylindrical bore for the threaded receipt of a cylindrical machine screw. However, so far as is known, no presently available screw head nail is able to accommodate a cylindrical machine screw in an effective and working manner.
As shown in the hypothetical comparison examples of FIGS. 1 and 2 drawings, if a nail 10 composed of a nail shank 12 having a point at one end 14 and a nail head 16 at its other end is provided with a threaded cylindrical bore 18 and is hammered via hammer 19 into a workpiece 11, the hammered end 16 becomes deformed, as a result of which the threaded cylindrical bore 18 formed therein would become clogged and deformed, rendering it unusable for the intended purpose of inserting a machine screw therein. This is not a problem with screws having a cylindrical machine screw threadably received in the screw head, because the screw head is not hammered, and as a result, the cylindrical bore opening is not deformed or clogged.
Indeed, no one has discovered or addressed the problem of enabling a nail to have a cylindrical machine screw received in its nail head, which nail head must often be hammered and flattened during installation. In both of the known cases discussed above, the use of a tapered screw bore and the use of a tapered screw would still allow the screw to be inserted into the screw hole without too much problem, since the narrow tip of the tapered screw could still be threaded into the flared opening of the screw past any deformation. However, the same is not true with the use of a cylindrical machine screw.